A drunken driver careening down the Belt Parkway at 100 mph flipped his car yesterday, killing his girlfriend and a male friend and severely injuring another passenger, police said.

Aleksander Yudovin, 20, of Brooklyn, lay handcuffed to his hospital bed in stable condition yesterday as he recovered from the horrific smashup. He was charged with manslaughter, reckless endangerment and DWI.

His girlfriend, Svetlana Kaushanskaya, 20, of Brooklyn, died, along with a young man in the back seat, police said.

The dead passenger’s girlfriend, Pauline Yefuk, 20, was taken to Kings County Hospital in extremely critical condition.

Kaushanskaya’s tearful 18-year-old sister, Inna, said, “We saw her last night and now she’s gone. I just want her back.”

After partying at Yefuk’s Sheepshead Bay home, the two couples got into Yudovin’s black Nissan Altima around 5 a.m. and began speeding east on the Belt, according to police.

As the car passed Flatbush Avenue in Marine Park, it crashed through a barricade in the middle of the parkway, overturned and landed in the westbound lane, police sources said.

Yudovin told The Post the offending car was a taxi – and he denied being drunk. But Yudovin’s breath wreaked of booze, cops said. Results of a hospital blood test were being analyzed yesterday.

Inna visited Yudovin – whom she described as “a really nice guy” – in the hospital, where he was recovering from facial wounds and a broken arm.

“He just kept asking, ‘How’s your sister? How’s your sister?’ ” the teen recalled. “I didn’t want to tell him she passed away.” When she asked him whether he and his friends had been drinking, “he kind of just nodded his head – but I guess because he didn’t really know what was going on,” she said.

Kaushanskaya had been dating Yudovin about a week, said Inna.

The group of friends started their night at Kaushanskaya’s family home and left just after her father gave them gas money. Later, she called home from the road.

“She said, ‘Hey, you want to hear something funny? We ran out of gas and now we’re pushing the car,’ ” recalled a tear-stricken Inna. “That was the last we heard.”

Services are being held for Kaushanskaya today at Nevsky Memorial Chapels in Brooklyn.